The present application relates to semiconductor processing; more particularly to a method of etching hard mask materials with fidelity to high aspect ratio patterns having small pitch features on the order of 40 nm or less.
For several decades now, the semiconductor industry has sought continued miniaturization. As critical dimensions and related pitches have shrunk, greater exactitude in etching has been required. In small scale etching, a pattern defect known as wiggling can arise. This type of pattern deformation is due to the uncontrolled release of hydrogen and/or oxygen from the organic soft masks used to transfer the pattern onto materials such as dielectrics. The result is line edge roughness (LER) and/or line width roughness (LWR) defects in the final patterned product.
There is thus a need to provide a process that will transfer small pitch pattern features from an organic soft mask to a hard mask material without pattern wiggling and resultant LER and/or LWR.